2914-69-4Relevant articles and documents
Electrical and mechanical anharmonicities from NIR-VCD spectra of compounds exhibiting axial and planar chirality: The cases of (S)-2,3-pentadiene and methyl-d3 (R)- and (S)-[2.2]paracyclophane-4-carboxylate
Abbate, Sergio,Longhi, Giovanna,Gangemi, Fabrizio,Gangemi, Roberto,Superchi, Stefano,Caporusso, Anna Maria,Ruzziconi, Renzo
, p. 841 - 849 (2011)
The IR and Near infrared (NIR) vibrational circular dichroism (VCD) spectra of molecules endowed with noncentral chirality have been investigated. Data for fundamental, first, and second overtone regions of (S)-2,3-pentadiene, exhibiting axial chirality, and methyl-d3 (R)- and (S)-[2.2]paracyclophane-4-carboxylate, exhibiting planar chirality have been measured and analyzed. The analysis of NIR and IR VCD spectra was based on the local-mode model and the use of density functional theory (DFT), providing mechanical and electrical anharmonic terms for all CH-bonds. The comparison of experimental and calculated spectra is satisfactory and allows one to monitor fine details in the asymmetric charge distribution in the molecules: these details consist in the harmonic frequencies, in the principal anharmonicity constants, in both the atomic polar and axial tensors and in their first and second derivatives with respect to the CH-stretching coordinates. Chirality, 2011. 2011 Wiley Liss, Inc. Copyright
Enantioselective oxidation of secondary alcohols by the flavoprotein alcohol oxidase from Phanerochaete chrysosporium
Tjallinks, Gwen,Martin, Caterina,Fraaije, Marco W.
, (2021/05/03)
The enantioselective oxidation of secondary alcohols represents a valuable approach for the synthesis of optically pure compounds. Flavoprotein oxidases can catalyse such selective transformations by merely using oxygen as electron acceptor. While many flavoprotein oxidases preferably act on primary alcohols, the FAD-containing alcohol oxidase from Phanerochaete chrysosporium was found to be able to perform kinetic resolutions of several secondary alcohols. By selective oxidation of the (S)-alcohols, the (R)-alcohols were obtained in high enantiopurity. In silico docking studies were carried out in order to substantiate the observed (S)-selectivity. Several hydrophobic and aromatic residues in the substrate binding site create a cavity in which the substrates can comfortably undergo van der Waals and pi-stacking interactions. Consequently, oxidation of the secondary alcohols is restricted to one of the two enantiomers. This study has uncovered the ability of an FAD-containing alcohol oxidase, that is known for oxidizing small primary alcohols, to perform enantioselective oxidations of various secondary alcohols.
Asymmetric hydrogenation of alkynyl ketones with the η6- arene/TsDPEN-ruthenium(II) catalyst
Arai, Noriyoshi,Satoh, Hironori,Utsumi, Noriyuki,Murata, Kunihiko,Tsutsumi, Kunihiko,Ohkuma, Takeshi
supporting information, p. 3030 - 3033 (2013/07/26)
Enantioselective hydrogenation of alkynyl ketones catalyzed by Ru(OTf)(TsDPEN)(η6-p-cymene) (TsDPEN = N-(p-toluenesulfonyl)-1,2- diphenylethylenediamine) affords the propargylic alcohols in up to 97% ee. The alkynyl moieties are left intact in most cases. The reaction can be conducted with a substrate-to-catalyst molar ratio as high as 5000 under 10 atm of H 2. The mode of enantioselection is elucidated with the transition state models directed by the CH/π attractive interaction between the substrate and the catalytic species.
